The purpose of this project is to contribute to the understanding of hormone action in metabolic processes in normal breast tissue under various conditions and to understand why hyperplastic or neoplastic breast tissue under the same conditions fails to respond to hormones or responds in an aberrant way. Among the topics studied are the response of mammary tissue in culture to hormones in terms of nucleic acid, protein, phosphoprotein, sialoglycoprotein, glycoprotein and glycosaminoglycan synthesis. The kinds of proteins made by mammary tissue in various stages of differentiation and by neoplastic mammary tissue are being analyzed. Analysis of human milk and formalin-fixed human breast tissue is in progress.